As is commonly known in the field, wood pulp fibers and super absorbent polymers can be made into absorbent paper through a binding process by heat or glue to be used as the absorbent material in hygiene pads, wherein the absorbent paper can satisfy the liquid-absorbing goal of the hygiene pads. Several advantages exist in using absorbent paper as the absorbent material in hygiene pads: the super absorbent polymers are placed evenly in the absorbent material used in hygiene pad products; the super absorbent polymers are fixed tightly inside the absorbent material; and the absorbent capacity of the hygiene pads using the absorbent material is high.
Drawbacks also exist in using absorbent paper as the absorbent material in hygiene pads, such as the speed of making absorbent paper is low. For instance, the speed of making absorbent paper is 50-70 meters/min using current technology and the speed of making hygiene pads is 120-180 meters/min and therefore, it is impossible to make absorbent paper while simultaneously make hygiene pads on one manufacturing line. Therefore, it is required to produce the absorbent paper in advance using one device and then put the absorbent paper into another device to make hygiene pad products; thus the cost of using this method is very high. Moreover, the length of each roll of the pre-made absorbent paper may be limited and, therefore, a manufacturer has to constantly change the rolls of the absorbent paper. Furthermore, this causes more waste and lowers the quality of the final products. Additionally, using pre-made absorbent paper requires additional packaging, storage and transportation before it can be put into the device used to manufacture hygiene pads and therefore, it causes negative consequences such as an increased cost to make hygiene pads, greater risks in affecting the quality of the hygiene pads, and more potential safety hazards.
A method and technology of making absorbent paper is disclosed in the international patent application WO1999/025281, wherein “the fabric material” stated in the application is a type of the absorbent paper referred in our field of industry.
Another method that the industry currently uses for manufacturing absorbent material is to make the absorbent material on the same manufacturing line that is manufacturing the hygiene pads. One advantage of this method is that the production speed is high, wherein the speed in making absorbent material can reach 120-180 meters/min. The cost is also low and the superior product rate is high because the manufacturing of the absorbent material and the final hygiene pads can be made continuously on the same manufacturing line.
However, unlike the absorbent material using absorbent paper, the wood pulp fibers and the super absorbent polymers in the absorbent material produced by this method may not be evenly distributed. Moreover, less super absorbent polymers can be put into the absorbent material made by this method, and the super absorbent polymers may not be tightly fixed inside the absorbent material such that the super absorbent polymers could move around and pile together inside the pad. Consequently, the absorbent material's capability to absorb liquid may be greatly decreased by this method. Additionally, the hygiene pad using the absorbent material may not consistently absorb liquid and therefore, the comfort level provided to the user by the hygiene pad made with such absorbent material is relatively low.
As the supply of natural resources becomes more and more limited, hygiene pads are developed to be manufactured with a lighter and thinner design. To make lighter and thinner hygiene pads, it is desired to have a smaller amount of wood pulp fibers and a much larger amount of super absorbent polymers in the absorbent material. Moreover, when making absorbent materials and hygiene pads on the same manufacturing line, the process of simply increasing the amount of super absorbent polymers used by the traditional method does not achieve the same liquid-absorbing function provided by the hygiene pads using absorbent paper as the absorbent material.
The current invention has found a way to develop a new method that successfully incorporates the manufacturing of absorbent paper into one manufacturing line that is also used to manufacture hygiene pads, achieving the result of a more consistent liquid-absorbing function while largely reducing the cost of production.